Apparatus for conditioning well bores



Jan. 7, 1964 A. w. KAMMERER 3,116,800

APPARATUS FOR CONDITIONING WELL BORES Filed Dec. 12, 1960 2 Sheets-Sheet 1 Ft 6. g0:

' "II/II INVENTOR. flea/E2 W K/IMMEQEQ Jan. 7, 19 4 A. w. KAMMERER APPARATUS FOR CONDITIONING WELL BORES 2 Sheets-Sheet 2 m A Wm; W M m WW6 w Filed Dec. 12, 1960, Ser. No. 75,261 13 Claims. (Cl. 175317) The present invention relates to apparatus for performing various operations in well bores, such as drilling, milling, hole enlarging and cementing.

An object of the invention is to provide apparatus capable of performing a cutting operation in a well bore, to provide an open region therewithin, jetting of fluid under hi h velocity against the wall of the well bore, and circulating fluid through the lower end of the apparatus so that it is capable of washing away bridges, and the like, that might develop as the result of the jettin' action of the fluid.

AnoLher object of the invention is to provide apparatus capable of performing a cutting operation in a well bore, to provide an open region therein, the apparatus having a relatively large passage area through which fluid can be pumped during the cutting operation, this passage area being considerably reduced to produce a jetting action of fluid at a comparatively high velocity against the wall of the open bore, while still permitting the circulating fluid to discharge through the lower end of the apparatus for the purpose of removing sand bridges and similar obstructions that might be present in the well bore below the apparatus.

A further object of the invention is to provide an apparatus having a relatively large passage area through which fluid can be pumped in an open well bore, this passage area being considerably reduced to produce a jetting action of fluid at a comparatively high velocity against the wall of the well bore, but still permitting circulating fluid to discharge through the lower end of the apparatus for the purpose of removing sand bridges and similar obstructions that might be present in the well bore below the apparatus during the time that the jetting action is occurring.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of several forms in which it be embodied. Such forms are shown in the drawings accompanying and forming part of the present specification. These forms will now be described in detail for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a side elevation of an apparatus disposed in a well bore, a portion being shown in section;

MG. 2 is an enlarged longitudinal section taken along the line 2-2 on FIG. 1;

FIG. 3 is an enlarged fragmentary cross-section taken along the line 3-3 on FIG. 2;

FIG. 4- is a bottom plan view of the apparatus disclosed in FIG. 1, on an enlarged scale;

FIG. 5 is a longitudinal section through a modified portion of the apparatus illustrated in FIG. 1;

FIG. 6 is a longitudinal section of the lower portion of still another form of the invention;

FIG. 7 is a combined side elevational view and longitudinal section through yet another embodiment of the invention disposed in a well bore;

FIG. 8 is an enlarged cross-section taken along the line i58 on FIG. 7.

" tilted States Patent Uni-ice Eilhfihd Patented Jan. '7, 1964 As disclosed in the drawings, an apparatus A is illustrated which is capable of performing a cutting operation in a well bore B while circulating ample fluid down through a string of drill pipe C, or similar tubular string, connected to the apparatus, for the purpose of removing cuttings, and the like, from the tool. After the desired cutting operation has been performed in the well bore, the passage area through the apparatus is materially restricted so that fluid under high velocity can be jetted out through generally radial or lateral nozzles in the apparatus, acting against the wall of the well bore for the purpose of cleaning it of drilling mud, and the like, or of enlarging its diameter, and also for the purpose of depositing cementitious material in the well bore to form a plug therein.

During the time that the jetting action is occurring, it is desired to still be capable of discharging fluid in a generally longitudinal direction from the lower portion of the apparatus to enable the well bore to be cleared of any obstructions that might exist or be produced by the apparatus, so that the apparatus can be moved both downwardly and upwardly in the well bore during the jetting action. Despite the restriction in the flow from the apparatus, so that high velocity jets are present for action against the wall of the well bore, the tool can be cleaned of cementitious material and other substances whenever desired by pumping fluid through the apparatus, capable of passing through a comparatively large area, insuring that a large volume of fluid is availed of for the purpose of appropriately cleaning or otherwise conditioning the apparatus.

In the form of invention illustrated in FIGS. 1 to 4, inclusive, the apparatus A is disclosed as constituting a milling tool, which may be of any desired type, as, for example, a milling tool illustrated in United States Patent No. 2,855,994. This tool is rotated by attaching the upper threaded box ll) of its body 11 to the lower pin end 12 of the string of drill pipe C, or corresponding tubular string, extending to the top of the well bore. The milling or cutting tool has circumferentially spaced cutting blades l3 extending generally radially or laterally of the body, which have lower cutter edges 14 adapted to engage a liner (not shown), or the like, for the purpose of milling away the liner upon rotation of the drill pipe and the apparatus and pumping of drilling fluid down through the drill pipe and through the apparatus, the drilling fluid passing upwardly around the apparatus A, carrying the cuttings upwardly with it and around the drill pipe C to the top of the well bore B.

As illustrated in HQ. 1, the milling tool has already milled away a desired length of liner (not shown) to expose the wall of the surrounding well bore B, in which the milling tool is illustrated as being located. The fluid pumped down through the drill string C and through the central passage 15 of the body 11 of the apparatus can discharge in a generally radial or lateral direction through one or a plurality of jetting nozzles 16 extending through the wall of the body of the tool below the cutting blades 13, the nozzles being suitably secured to the body, as by welding or brazing. The fiuid can also pass through the central body passage 15 to its lower portion 17 where it will flow through a lower nozzle 18, inserted upwardly in the lower end of the tapered guide or nose portion 19 of the body, and through a noncircular passage 2t) in the lower part of the nozzle, which is surrounded by an upwardly facing seat 21.

During the time that the apparatus A is being lowered in the well bore on the string of drill pipe, the passage 2 19 through the lower nozzle 18 is open. Accordingly, fluid can enter the body passage 15 freely for upward movement into the drill pipe C. In the form of inven tion disclosed in FIGS. 1 to 4, inclusive, such fluid can also pass through the jetting nozzles 16, which are of a comparatively restricted area, opening into the central passage through the body. Similarly, alter the apparatus has been lowered into engagement with the liner for the performance of the milling operation, it is rotated and an ample quantity of drilling fluid pumped down through the drill pipe C, flowing through the central passage 15 of the body and simultaneously through the full open area of the lower nozzle 18 and through the jetting nozzles 16, a large portion of the fluid passing down through the lower nozzle 18. The circulating fluid will then pass upwardly around the body 11 of the tool and the cutters 13, carrying the cuttings upwardly through the well bore B to the top thereof. During the time that the milling action is occurring, the jetting nozzles 16 will be impinging some fluid against the wall of the liner below the lower cutting edges 14- of the cutting blades 13. However, such jetting action may have very little effect on the liner.

After the wall of the well bore has been exposed by milling away a certain length at the liner, the tool A is elevated in the well bore so that the jetting nozzles can impinge fluid against the wall of the open well bore, for the purpose of conditioning it. To insure that fluid will issue at a comparatively high velocity through the jetting nozzles 16, the passage through the lower nozzle 33 is restricted by lowering or pumping a valve ele'ient 23, in the form of a ball, down through. the drill pipe C, Which will come to rest upon the Seat 21 in the lower nozzle 18. Due to the non-circular shape or the lower passage 29 in the nozzle, the ball will not close such passage, but will merely restrict its area, allowing some fluid to still pass down through the nozzle 18 and discharge in a downward direction into the well bore B. The restriction in the area through the lower nozzle 18 will cause an increase in the velocity of the fluid discharging substantially radially from the jett'ng nozzles 15, such fluid impinging upon the wall of the well bore B and cleaning it of drilling mud, and the like. If desired, the fluid can be used to enlarge the diameter of the well bore B. During the jetting action of the fluid from the radial nozzles 16 against the wall of the well bore, and drill pipe C and the apparatus A are rotated so that the nozzles cover the full circumference of tie well bore, and the tool is moved longitudinally in the open well bore alons a desired length. Thus, the tool can be raised in the well bore and fluid jetted through its nozzles 16. and it can also be lowered therewithin, the tool being raised and lowered as often as is deemed necessary for the purpose of appropriately conditioning the well bore B.

The jetting action against the wall of the well bore might dislodge formation material, which will ordinarily occur in the event that the jetting action results in an enlargement in diameter of the well bore B. The fluid issuing from the jetting nozzles 16 will carry the formation cuttings upwardly around the apparatus A and the drill pipe C to the top of the well bore B. However, some of the formation material may drop downwardly into the well bore and form a bridge which would tend to restrict or prevent downward movement of the apparatus A in the well bore. In the event that lowering of the apparatus causes it to encounter a bridge, and despite the presence of the ball member 23 on the seat 21, a sullicient quantity of fluid will still by-pass around the ball or flow restricting member, and through the nozzle 13, acting upon the bridge material for the purpose of washing it away and circulating it upwardly around the apparatus and the string of drill pipe to the top of the hole.

After the open well bore B has been properly conditioned, it may be desired to deposit a cementitious plug (not shown) therewithin. This can be done without removing the apparatus from the well bore. The required quantity of cementitious material is pumped down through the drill pipe C, and the major portion of it will issue through the jetting nozzles and impinge against the wall of the well bore 13. During the time that the cementitious material is issuifi'g from the jetting nozzles into the open well bore, and starting from the lower region in the well bore at which the plug is to be formed, the drill pipe C and the apparatus A. are 1- "tated at the proper speed and the apparatus is gradually elevated in the well bore so that the cementitious material will strike the wall of the well bore and then sluif do'tyn't /ardly to form a solid cernentitious plug agrosa the e transverse area of the hole B. Sat the ce mentitrous material, such as cement slurry, w 1 also pass around theball member and discharge downwardlyin the well bore.

Thfi apparatus is elevated ,in the well here gradually While being rotated, until the required amount of cement slurry, or,the like, has been deposited in the well bore, a or which the apparatus can be elevated at sullicient disunce above the cement slurry to allow cleaning fluid to be umped down through the string of drill pipe and through the jetting nozzles 16 and the lower nozzle 13 and Wash the excess cement slurry out of the apparatus and upwardly out of the hole. lt desiied, the cleaning fiuid can be reversibly iii'rcul'ated, being pump-ed don/n wardly into the annulus 25 between the drillpipe C and the wall at the well bore B, the cleaning fluid flowing ihwardly through the jetpozzles 16 into the central passage 15 of the body, and also flowing upwardly through the lower nozzle 18, carrying the ball 23 upwardly with it. Any cemcntitious material in the tool and the ball or plug member 23, followed by the c '.culating fluid, will then pass upwardly through the drill pipe C for discharge at the top of the well bore. Such reverse CilfQlllfif tion of fluid can occur through use of a large volume of fluid and at a rapid rate, inasmuch as the upward removal of the ball 23 from the Seat 21 presents a much larger passage area for the flow of the cleaning fluid than is present when circulating fluid is pumped downwardly through the drill pipe for discharge in an outward direction through the radial jetting nozzles 16 and around the ball and through the lower nozzle 18.

Following the cleaning of the apparatus A, it can be removed from the well bore by elevating the string of drill pipe C the'rewithin, in a known manner.

The form of invention illustrated in FIG. 5 embodies a different fluid passage and nozzle structure at the lower end of the apparatus than disclosed in FIG. 1. It accomplishes the same purposes as the lower nozzle 13 and ball 23 in the apparatus illustrated in FIG. 1. In the apparatus shown in PI. 5, the lower portion of the central passage 15 through the body of the tool below the jetting nozzles 16 has a plurality of downwardly diverging branches 3d opening to the exterior of the body. In each of these branches, a nozzle fill, 32 is secured in any suitable manner, as by welding or brazing, each of these nozzles having an upper valve seat 33. During the action of cutting or milling away a liner, or other object in the well bore, fluid is pumped down through the drill string C and through the body passage 15, discharging radially through the jetting nozzles 16 and also through the nozzles 31, 32 into the well bore, the fluid carrying the cuttings upwardly around the apparatus A and the drill pipe C to the top or the hole B. During this time, a large passage area is available through which fluid can flow between the central passage 15 of the tool body Ill and the surrounding well bore, such passage area being the combined areas of the jetting nozzles 16 and of the lower nozzles 31, 32.

When fluid at a high velocity is to be discharged through the jetting nozzles 16, the area through which fluid can discharge from the lower portion of the tool is decreased. As specifically shown, a ball member 23, or the like, is lowered or pumped down through the drill pipe and will pass through the central passage 15 and come to rest against one or the other of the nozzle seats 33, losing the passage through such nozzle completely.-

As the result, jetting fluid can then only pass through the radial jetting nozzles 16 and through one of the lower nozzles, such as the nozzle 32. Thus, the velocity at which fluid now discharges through the jetting nozzles 16 has been increased, the jetting action occurring during the time that the drill pipe C and apparatus A are being rotated, and during the time that the apparatus is moved longitudinally in the well bore. Fluid is also discharged in a substantially longitudinal direction from the nozzle 32 that is not engaged by the valve ball 23, so that the fluid issuing therefrom in a downward direction can act upon any sand bridges, or the like, that might be produced by the jetting action of the iluid issuing from the upper nozzles llfi against the wall of the open formation, thereby insuring that the apparatus can be moved in an upward and downward direction along the desired length of the well bore in conditioning the well bore, increasing its diameter, or in depositing a cementitious plug in the well bore by dischargim the cementitious material throu h the jetting nozzles 16 and also through the lower nozzle 32 having the open passage.

After a cementing operation has been performed, the tool can also be elevated in the well bore above the discharged cement, and can be cleaned of cementitious material and other substances, either by pumping the long way down through the drill pipe C and out through the jetting nozzles 16 and the lower nozzle 32 that has an open passage, or lluid can be pumped down through the annulus 25 around the drill pipe C passing inwardly through the jetting nozzles 16 and upwardly through both of the lower nozzles B ll, 32, carrying the ball 23 upwardly through the central body passage and through the drill pipe C to the top of the well bore.

in the form of invention disclosed in PEG. 6, the lower nozzle 18 illustrated in FIG. 1 has been replaced by a central nozzle 4% in the lower end of the body passage 15, which is suitably secured to the body, and by a branching nozzle 4d disposed in a passage 42 communicating with the central body passage 15", and diverging from the body passage at a steep angle so as to direct its fluid predominantly in a downward direction. The lower nozzle ill has an upper valve seat 4-3 thereon and is adapted to be engaged by a valve member or element 23, such as a ball, that can be lowered or pumped down the string of drill pipe C and the body passage 15 into engagement therewith.

As in the other forms of the invention, the ball 23 is at first absent from the apparatus, allowing circulating fluid to pass from the body passage 15 through a comparatively large total passage area, including the areas of the upper radial jetting nozzles l6 and the areas of the lower nozzles 4h, ll. After a milling or other cutting operation has been completed in the well bore, and it is desired to have iluid jet from the radial nozzles 15 at a high velocity, the area through which fluid can discharge from the lower portion of the apparatus is decreased substantially, as by lowering or pumping the ball 2-3 down through the drill pipe and through the body passage 15 into engagement with the circular valve seat 4-3 in the lowermost nozzle 443, fully closing the passage of the latter. Fluid or cementitious material pumped down through the apparatus will now pass at a high velocity through the radial jetting nozzles 16, and such fluid will also pass in a predominantly downward direction through the inclined nozzle 41.

The apparatus disclosed in FIG. 6 operates in the same manner as in the other forms of the invention. In the event that a bridge, or the like, terms in the well bore below the apparatus, circulating fluid issuing through the branching nozzle 41 will strike such sand bridge, the apparatus being rotated while fluid is being discharged therefrom so as to wash the sand bridge away completely, the sand cuttings and circulating fluid therewithin being carried upwardly around the apparatus A and the drill pipe C to the top of the well bore.

As in the other forms of the invention, the apparatus can be cleaned whenever desired by pumping fluid therethrough, and the ball member 23 removed by reversely circulating fluid around the apparatus, such reversely circulating fluid passing upwardly through the lowermost nozzle 40 and carrying the ball upwardly through the body passage 15 and the drill pipe C to the top of the hole, leaving the initial unobstructed passage areas through the several nozzles 4t 41 available through which fluid can be pumped.

In the form of invention illustrated in FIG. 7, the string of drill pipe C is connected to a tubular body es, the lower end of which has a threaded box 61 for threaded connection to the upper pin end 62 of a drill bit 63 of any suitable type, the fluid passing through the entral passage 64 of the drill bit and through one or a plurality of its nozzles as for the purpose of removing any cuttings produced by the cutters 66 of the drill bit from the drilling region and flushing them upwardly around the apparatus and the drill pipe to the top of the Well bore B. The tubular body member as has a plurality of circumferentially spaced generally radial ports, each of which has a jetting nozzle 67 mounted therein and suitably secured, as by welding or brazing, to the body of the tool. These ports or nozzles are initiall closed by a sleeve valve member 68 disposed thereacross with its periphery sealing against side seal rings 6% above and below the ports. The sleeve valve 658 is retained initially in its closed condition across the ports or nozzles 67 by one or more shear screws 7% extending through the body and into the sleeve valve.

The lower portion of the sleeve valve 6% has a passage '71 therethrough of non-circular shape, and which, in fact, may have substantially the same shape as the passage Zll in the lower nozzle it? in the form of invention disclosed in FIGS. 1 to 4, inclusive. During the time that the drilling or other action is bein performed with the apparatus'shown in FIG. 7, all of the circulating pumped down through the drill pipe C passes through the body member 6% and the sleeve valve 63 into the drill bit passage 64, discharging from its nozzles 65 to wash the cuttings away from the drilling region and upwardly around the apparatus and tie drill pipe to the top of the hole.

When a jetting action is to be performed against the wall of an open formation, a flow restricting or valve member 23, such as a ball, is lowered or pumped down through the string of drill pipe, coming to rest upon the seat 72 in the sleeve valve. This ball member does not close the lower passage 71 through the sleeve valve, but merely restricts the effective area of the passage. Some fluid can still pass around the ball 23 and out through the sleeve valve 68 for continued downward movement through the body as and the drill bit 63, discharging from the nozzles 65 of the latter. Because of the restricted area through the sleeve valve as, the pumping of fluid at a sufficient rate through the drill pipe and the apparatus will cause a back pressure to build up, acting upon the sleeve valve as and the ball member 23, suilicient to shear the screw 76 and shift the sleeve valve 655 and the ball valve member 23 downwardly until the sleeve valve member engages an upwardly facing stop shoulder 74 in the body member, at which time the sleeve valve will be disposed below the radial jetting nozzles 67. The jetting fluid can now be pumped through the jetting nozzles for action upon the Wall of the well bore. Some fluid will still by-pass around the ball member 23, continuing to flow downwardly through the bit passage 64- and from its nozzles es.

The apparatus illustrated in H83. 7 and 8 can be used in substantially the same manner as all of the previously described forms of apparatus. The drill pipe C and the apparatus A are rotated and moved longitudinally in the Well bore B so that the fluid jetting from the radial nozzles 67 can condition the wall of the well bore B or enlarge its diameter, or the pumping or the cementitious material through the nozzles will cause such cementitious material to impinge against the wall of the well bore and then slull downwardly into the well bore to form a bridge therewithin. Some of the fluid is still by-passing around the ball valve element 23 and flowing downwardly through the drill bit 63 and its nozzles 65' to wash away any bridges, or the like, that might form in the well bore, so as not to impede upward and downward movement of the apparatus in the well bore and its rtation while the jetting action is being performed.

As in the other forms of the apparatus, in the event it is used for pumping ceinentitious material into the well bore, it can be cleaned of such cementitious material by pumping fluid down through the drill pipe C and the apparatus A, the fluid passing through the jetting nozzles 67, and also around the ball valve member 23 and through the drill bit 6?, to clean all regions of the apparatus of the eernentitious material. Similarly, as in the other forms of the invention, circulating t can also be pumped down through the annulus 25 around the drill pipe C passing inwardly through the radial jetting nozzles 6'7, and also in through the drill bit nozzles 65, flowing upwardly through the drill bit passage 6 and the body passage and sleeve 68, carrying the ball 23 upwardly with it through the drill pipe C to the top of the well bore, thereby leaving an unobstructed passage through the apparatus, which now may, if desired, be removed from the well bore.

In all forms of the apparatus, after the flow restricting valve member 23 has been pumped out of the well bore, elevation of the drill pipe C will result in fluid drainage therefrom into the well bore through all flow passage areas in the apparatus, so that the chance of pulling a Wet string at the top of the hole is greatly reduced, if not completely eliminated.

I claim:

1. In apparatus adapted to be lowered in a well bore 011 a tubular string: a fluid jetting device including a rotary drill bit having cutting means thereon for performing a cutting action in the well bore; said device having a fluid passage adapted to receive fluid from the tubular string and including a generally radial nozzle below said cutting means for directing fluid from the passage against the wall of the well bore; means in said device below said nozzle and communicating with said passage for discharging fluid from the lower portion of the device in a downward direction into the well bore; and rigid means engageable with said discharging means for partially closing said discharging means to restrict the flow of fluid therethrough.

2. In apparatus adapted to be lowered in a well bore on a tubular string: a fluid jetting device including a rotary drill bit having cutting means thereon for performing a cutting action in the well bore; said device having a fluid passage adapted to receive fluid from the tubular string and including a generally radial nozzle below said cutting means for directing fluid from the passage against the wall of the well bore; initially open means in said device below said nozzle and communicating with said passage for discharging fluid from the lower portion of the device in a downward direction into the well bore; and rigid means movable downwardly through the tubular string and passage into engagement with said discharging means for partially closing said discharging means to restrict the flow of fluid therethrough.

3. In apparatus adapted to be lowered in a well bore on a tubular string: a fluid jetting device including a r0- tary drill bit having cutting means thereon for performing a cutting action in the well bore; said device having a fluid passage adapted to receive fluid from the tubular string and including a generally radial nozzle for directing fluid from the passage against the wall of the well bore; initially fully open means in said device below said nozzle and communicating with said passage for discharg- 8 ing fluid from the lower portion of the device in a downward direction into the well bore; and rigid means movable downwardly through the tubular string and passage into engagement with said discharging means for partially closing said discharging means to restrict the flow of fluid therethrough.

4. In apparatus adapted to be lowered in a well bore on a tubular string: a fluid jetting device including a rotary drill bit having cutting means thereon for performing a cutting action in the well here; said device having a fluid passage adapted to receive fluid from the tubular string and including a generally radial first nozzle below said cutting means for directing fluid from the passage against the wall of the well bore; an initially open second nozzle in said device below said first nozzle and communicating with said passage for discharging fluid in a downward direction into the well bore; and means engageable with said second nozzle for partially closing said second nozzle to restrict downward flow of fluid therethrough.

5. in apparatus adapted to be lowered in a well bore on a tubular string: a fluid jetting device including a rotary drill bit having cutting means thereon for performing a cutting action in the well bore; said device having a fluid passage adapted to receive fluid from the tubular string and including a generally radial first nozzle below said cutting means for directing fluid from the passage against the wall of the well bore; an initially open second nozzle in said device below said first nozzle and communicating with said passage for discharging fluid in a downward direction into the well bore, said second nozzle having a non-circular passage; and flow restricting means engageable with said second nozzle and disposed across said non-circular passage to partially close said non-circular passage and direct fluid around said flow restricting means and through said passage into the well bore.

6. In apparatus adapted to be lowered in a well bore on a tubular string: a fluid jetting device including a 1'0- tary drill bit having cutting means thereon for performing a cutting action in the well bore; said device having a fluid passage adapted to receive fluid from the tubular string and including a generally radial first nozzle below said cutting means for directing fluid from the passage against the wall of the well bore; a plurality of nozzles in said device below said first nozzle and communicating with said passage for directing fluid in a downward direction into the well bore; and rigid means engageable with one of said plurality of nozzles for closing the same.

7. In apparatus adapted to be lowered in a well bore on a tubular string: a fluid jetting device including a rotary drill bit having cutting means thereon for performing a cutting action in the well bore; said device having a fluid passage adapted to receive fluid from the tubular string and including a generally radial first nozzle below said cutting means for directing fluid from the passage against the wall of the well bore; a plurality of nozzles in said device below said first nozzle and communicating with said passage for discharging fluid in a downward direction into the well bore; and rigid means engageable with one or" said plurality of nozzles for closing the same.

8. In apparatus adapted to be disposed in a well bore on a tubular string: a rotary drill bit having cutting means thereon for performing a cutting action in the well bore and havim a fluid passage adapted to receive fiuid from the tubular string; a generally radial nozzle in said bit communicating with said passage and disposed substantially normal to the bit axis for directing fluid against the wall of the well bore; initially open nozzle means in said bit below said nozzle and communicating with said passage for directing fluid downwardly in the well bore; and rigid means engageable with said nozzle means for partially closing said nozzle means to restrict downward flow of fluid therethrough.

9. In apparatus adapted to be disposed in a well bore in a tubular string: a rotary drill bit having cutting means thereon for performinng a cutting action in the well bore and having a fluid passage adapted to receive fluid from the tubular string; a generally radial first nozzle in said bit communicating with said passage and disposed substantially normal to the bit axis for directing fluid against the wall of the well bore; an initially open second nozzle in the lower portion of said bit below said first nozzle and communicating with said passage for discharging fluid in a downward direction into the well bore, said second nozzle having a non-circular passage; and flow restricting means engageable with said second nozzle and disposed across said non-circular passage to partially close said non-circular passage and cause fluid to flow around said flow restricting means and through said passage into the well bore.

10. In apparatus adapted to be disposed in a Well bore on a tubular string: a rotary drill bit having cutting means thereon for performing a cutting action in the well bore and having a fluid passage adapted to receive fluid from the tubular string; a generally radial first nozzle in said bit below said cutting means communicating with said passage and disposed substantially normal to the bit axis for directing fluid against the wall of the well bore; a plurality of nozzles in said drill bit below said first nozzle and communicating with said passage for discharging fluid in a downward direction into the well bore; and rigid means engageable with one of said plurality of nozzles for closing the same.

11. In apparatus adapted to be lowered in a well bore on a tubular string: a fluid jetting device including a rotary drill bit having cutting means thereon for performing a cutting action in the Well bore; said device having a fluid passage adapted to receive fluid from the tubular string and including a generally radial nozzle below said cutting means for directing fluid from the passage against the wall of the well bore; means in said device below said nozzle and communicating with said passage for discharging fluid from the lower portion of the device at its lower terminus in a downward direction into the well bore; and rigid means engageable with said discharging means for partially closing said discharging means to restrict the flow of fluid therethrough.

12. In apparatus adapted to be lowered in a well bore on a tubular string: a fluid jetting device including a rotary drill bit having cutting means thereon for performing a cutting action in the well bore; said device having a fluid passage adapted to receive fluid from the tubular string and including a generally radial nozzle for directing fluid from the passage against the Wall of the well bore; means in said bit below said nozzle and communicating with said passage for discharging fluid from the lower portion of the bit at its lower terminus in a downward direction into the well bore; and rigid means engageable with said discharging means for partially closing said discharging means to restrict the flow of fluid therethrough.

13. In apparatus adapted to be lowered in a well bore on a tubular string: a fluid jetting device including a rotary drill bit having cutting means thereon for performing a cutting action in the well bore; said device having a fluid passage adapted to receive fluid from the tubular string and including a generally radial first nozzle below said cutting means for directing fluid from the passage against the wall of the Well bore; an initially open second nozzle in said device below said first nozzle and communicating with said passage for discharging fluid in a downward direction into the well bore; and means movable downwardly through the tubular string and passage into engagement with said second nozzle for partially closing said second nozzle to restrict downward flow of fluid therethrough.

References Cited in the file of this patent UNITED STATES PATENTS 851,999 Skellenger Apr. 30, 1907 2,116,408 OLeary et al. c May 3, 1938 2,153,034 Baker Apr. 4, 1939 2,238,895 Gage Apr. 22, 1941 2,307,658 Appleby Jan. 5, 1943 2,307,662 Balor Jan. 5, 1943 2,312,018 Beckman Feb. 23, 1943 2,315,496 Boynton Apr. 6, 1943 2,761,469 Hansen Sept. 4, 1956 2,834,578 Carr May 13, 1958 2,880,965 Bobo Apr. 7, 1959 

8. IN APPARATUS ADAPTED TO BE DISPOSED IN A WELL BORE ON A TUBULAR STRING: A ROTARY DRILL BIT HAVING CUTTING MEANS THEREON FOR PERFORMING A CUTTING ACTION IN THE WELL BORE AND HAVING A FLUID PASSAGE ADAPTED TO RECEIVE FLUID FROM THE TUBULAR STRING; A GENERALLY RADIAL NOZZLE IN SAID BIT COMMUNICATING WITH SAID PASSAGE AND DISPOSED SUBSTANTIALLY NORMAL TO THE BIT AXIS FOR DIRECTING FLUID AGAINST THE WALL OF THE WELL BORE; INITIALLY OPEN NOZZLE MEANS IN SAID BIT BELOW SAID NOZZLE AND COMMUNICATING WITH SAID PASSAGE FOR DIRECTING FLUID DOWNWARDLY IN THE WELL BORE; AND RIGID MEANS ENGAGEABLE WITH SAID NOZZLE MEANS FOR PARTIALLY CLOSING SAID NOZZLE MEANS TO RESTRICT DOWNWARD FLOW OF FLUID THERETHROUGH. 